It would be nearly impossible to catch a climber's fall without the added advantage of friction. For this reason, belay techniques have evolved from an old-fashioned wrap around your waist, to today's current variety of belay devices. These devices give the belayer an advantage while also distributing fall forces comfortably onto their harness.
Tube style belay devices are the most popular for several reasons. These devices work well with a large variety of ropes and can be used for top roping, leading, and rappelling. They are also the lightest and cheapest option available. Because of their versatility, a variety of models are available. An important note: certain models be can used in an auto-locking mode, which is used to belay two climbers who are seconding, for faster team multipitch ascents and topside belays.
